Ejector and nozzle therefor



July 22, 1924.

c. E. LUCKE EJECTOR AND NOZZLE THEREFOR Filed March 1, 1923 avwemtoz wan/M m m Game/ Patented July 22, 1924.

UNITED STATES PATENT OFFICE.

CHARLES E. LUCKE, OF NEW YORK, N. Y., ASSIGNOR TO WORTI-IINGTON PUMP AND MACHINERY CORPORATION, OF NEW YORK, N. Y., A CORPORATION OF VIRGINIA.

EJECTOR AND NOZZLE THEREFOR.

Application filed March 1, 1923.

ToaZZ whom it may concern.

Be it known that I, CHARLEs E. LUCKE, a citizen of the United States, residing at New York city, county of New York, and State of New York, have invented certain new and useful Improvements in Ejectors and Nozzles Therefor, fully described and represented in the following specification and the accon'ipanying drawings, forming a part of the same.

This invention relates to ejectors and nozzles therefor, and particularly to such ejectors of the class operated by a motive fluid such as water, or steam or other elastic fluid for compressing and discharging air or other gas or vapor, as, for instance, in withdrawing air and non-condensed vapor from a steam condenser and compressing the withdrawn fluid to atmospheric or other pressure for delivery.

One important object of the invention is to provide an improved ejector nozzle by which a single jet of any size may be used with the required entraining and compressing, efiiciency, thus making unnecessary the present practice of using multiple jets for a large capacity, and further to provide such an ejector nozzle which may be adjusted to different capacities without substantial sacrifice of such efliciency. While the invention is applicable to a water jetejector, it will be described more particularly as applied to steam jet ejectors.

The steam jet now usually employed is of circular section and the energy available for entraining and compressing is, for a given steam pressure and discharge pressure, substantially proportional to the cross-sectional area of the jet, that is to say, to the square of the diameter of the jet at such cross-section. On the other hand, the entraining surface of the jet is proportional to the perimeter, or circumference, ofthe crosssection, that is to say, to the first power of the diameter at such crosssection. The ratio of the perimeter to the area at the point of minimum cross-sectional area may be taken as one factor of the etiiciency of the jet. Increase 111 the diameter of such circular ets lowers their efficiency because the ratio of 4 the perimeter to the area, v12, decreases with increase of diameter, D, so that the steam used per pound of air compressed increases. In other words, the steam at the Serial No. 622,027.

central portion of the jet can do little or no entralning of air. As a result, it has become the common practice to use multiple steam jets of relative small diameter for ejectors of large capacity, all of the jets discharging into one diiluser or combining tube. This increases the size and complication of the apparatus and involves ditliculty in arranging the jets so as to secure free approach to all the jets of the air or other gas to be entrained and'compressed. Such circular jets, moreover, obviously cannot be adjusted for different capacities without varying the diameter of the jet tube in such a way as to change the character of the jet so that the efficiency is reduced.

Furthermore, on account of the wide dif- :t'erences encountered in the conditions of operation, as, for example, between starting and regular full load operation, it is not possible to employ a difiiuser or combining tube which will operate with high efiiciency under the varying conditions. Hence, theusual ejector has its diiluser or combining tube of a compromise design, so that it will continue to operate under varying conditions, but not with high efiiciency.

By the present invention it becomes possible to avoid the above mentioned difiiculties and to provide a construction of nozzle for use either as a jet nozzle or as a diffuser or combining tube, or both, which will permit the ready adjustment of the cross-sectional area of such nozzle or nozzles to any value between the limits for which such nozzle or nozzles is or are designed, while at the same time simultaneously adjusting the perimeter of the said cross-section in nearly or substantially the same proportion as the area is changed, so as to maintain as nearly as possible a constant ratio of perimeter to area. In practice it is possible to design a nozzle whose throat or minimum cross-sectional area may be increased 100%, with less than a two per cent drop in ratio of perimeter to area, at said cross-section.

In accordance with the present invention, such a nozzle is made with two short sides and two very much longer sides, its longer sides being parallel in cross-section and either straight or curved, so that the nozzle will have a cross-section forming a more or less long and narrow strip of jet space. The width of this space strip is fixed at a value as small as possible consistent with avoiding excessive wall friction losses- The length of the space strip is made great enough for the fluid capacity required. If the width of such space strip is very small in proportion to the length, the ratio of area to perimeter approaches a constant value for any length of strip, so that such. jets can be given the best ratio of width to length for efficient entraining and compressing purposes, and this ratio can be substantially maintained regardless of the weight of steam passing through the jet, or the size of the jet, and thus the length may be adjusted relatively'to a constant width of to suit the capacity, without substantial loss of efliciency. lVhen such a nozzle is used as an operating or jet nozzle, a corresponding construction of nozzle for the diffuser or com bining tube is preferably used, the expansion or contraction of the tube being in the same planes as that of the jet nozzle, and

the length of the diffuser space in cross section may be adjustable relatively to a constant width, as in the case of the steam jet.

By the statement hereinabove made that the expansion or contraction of the com- .bining tube is inthe same planes as that of the jet nozzle, is meant that both nozzles are so arranged relative to each other that an imaginary plane through the jet space of one nozzle parallel to those sides of such nozzle which are at the same distance apart throughout the length of the nozzle will also be parallel to the corresponding or similarly related sides of the other nozzle, so that the expansion or contraction of the fluid in both nozzles will be in the direction of the homologous transverse axes of the two nozzles.

In the actual manufacture of steam jet ejectors, it is necessary to meet a very wide variety of steam and air capacities, and of pressure and quality of steam supplied, pressure and amount of air entering the diffuser tube and fuel delivery pressure. This difficulty is multiplied when multistage ejectors are used, as is now common aractice. As a result, the steam nozzles and diffuser tubes, which must always be produced with greataccuracy as to diameters and angles of divergence or convergence, are expensive to make in the required varieties and degrees of accuracy and it is often necessary to use stock nozzles and tubes that are not exactly suited to the condition, to save excessive costs, but with sacrifice of e'fliciency. In case an error is made it is not possible to correct it, and in case operating conditions are changed after installation, it cannot be met, and the ejector is either of wrong capacity or very ineflicient, or both, even though it may have been right at first.

-When the fluid jet is made, as in my ejector, in the slot between two walls spaced apart as little as possible consistent with avoiding excessive percentages of jet energy loss due to wall friction, the ejector is e'fiicient for any length of such slot, and any required capacity is obtained merely by de tel-mining the length of the slot which may also be adjustable by hand. Any change of for purpose of illustration, a steam jet air ejector embodying the invention in one of its preferred forms, and this construction will now be described and the features form-' ing the invention then specifically pointed out in the claims.

In the drawing Figure 1 is a cross section of the ejector with the steam nozzle in elevation, on the line 1-1 of Fig. 2;

Figure 2 is a central section on the line Q2 of Fig. 1, the central portion being broken away;

Figures 3 and 42 are cross sections on, respectively, lines 3 and 4: of Fig. 2, also partly broken away;

Figure is a cross section on the line 5-5 of Fig. 1, partly broken away; and

Figure (3 is a diagram illustrating a very suitably proportioned jet slit for one type of nozzle.

Referring to the drawings, A is the steam chamber with inlet l0, B the operating or jot nozzle, C the combining chamber receiving air and uncondenscd vapor from the condenser, or other fluid to be entrained and con'iprcssed, through the inlet 11, and D the nozzle serving asa diffuser or combining tube in which the energy of velocity is converted into the work of compression and from which the combined fluids are dis charged to the atmosphere or a suitable receiver, or to a second ejector stage. The

operating or jet nozzle is shown as of the diverging type, and the nozzle serving as a combining tube D as of the convergingdiverging type, but these may be varied, as well understood in the art, in accordance with the fluids handled and their relative pressures.

The jet nozzle is formed with a com-paratively narrow and relatively elongated steam space a, formed by the fixed side walls 12 and the end walls 13, one or both of which end walls 13 are preferably made adjustable so as to vary the length and area of the nozzle space a, to vary the capacity without substantially changing the character of the steam jet and thus impairing its efliciency. As shown, both the end walls 13 are made adjustable by hand operated screws 14: pro- Vided with looking nuts, so that the end walls 13 may be adjusted to the desired position and securely locked therein. The screws on the two walls are shown as adjustable independently of each other, but obviously they may be arranged for adjustment of both simultaneously by a single operating means.

The jet nozzle above described may be used with any suitable difluser or combining tube, and the latter may be adjustable or not, but preferably and for the best results under all conditions the diffuser or combining tube is similarly made, as shown in Fig. 4, with a relatively narrow andelongated combining space Z) formed by fixed side walls 15 and movable end walls 16, both of said end walls being made adjustable by hand operated screws 17, as in the case of the steam jet. The adjustable end walls 13 and 16' are packed in any suitable manner against leakage, as indicated at 1.

It will be understood that the drawings are largely diagrammatic and that the width ofthe steam and combining spaces respectively have been exaggerated relatively to their lengths, in Figs. 1 to 5, for purpose of illustration, and that the construction shown and described is only for purpose of illustration of one embodiment of the invention, and may be varied widely within the invention as defined by the claims.

Fig. 6 gives diagrammatically an idea of what the proportions of the jet slot may be in cross-section to obtain the full benefits of the invention. If it be assumed that when jet orifice, the length of the slot will be 25 times the width of the slot, and when the end walls are adjusted away from each other where the length of the jet slot is 50 times the width of the slot, there can be obtained a variation in slot area of one hundred per cent-that is to say, the maximum jet area at the smallest section will be double the minimum jet area at the same section, while, on the other hand, the ratio of perimeter of slot to area of slot has changed less than 2 per cent. Of course, at other cross-sections of the jet, the variation in said ratio will be greater depending upon the slope of the inner walls of the nozzle, but by keeping the width as small as possible consistent with a small loss of jet energy due to wall friction, and obtaining the desired cross-sectional area of jet by using a slot which is long relative to its width, the variation in the ratio of perimeter to area may be kept relatively low, and hence the variation in efliciency may be maintained within satisfactory limits. In Fig. 6 the slot is indicated as about 0.1 inch in width, and at its minimum area it has a length of 2.5 inches, while at its maximum area it has a length of 5 inches. This principle applies both to the jet nozzle and to the diffuser or combining tube.

WVhat is claimed is:

1. An ejector having an operating fluid nozzle and combining tube, each formed with at least two opposite sides parallel to each other in cross-section, the expansion or contraction of the operating fluid nozzle and combining tube being in the same planes.

2. An ejector having an operating fluid nozzle and a diffuser or combining tube, each formed with at least two opposite sides parallel to each other in cross-section, the expansion or contraction of the. operating fluid nozzle and combining tube being in the same planes, and means for adjusting the length of the space between the two parallel opposite sides of the operating fluid nozzle to vary its. capacity.

3. An ejector having an operating fluid nozzle and a difi'user or combining tube, each formed with at least two opposite sides parallel to each other in cross-section, the expansion or contraction of the operating fluid nozzle and combining tube being in the same planes, and means for adjusting the length of the space between the parallel opposite sides of the nozzle and tube to vary their capacity.

4. An ejector having a nozzle formed with a fluid space elongated in cross section and its opposite w'allsdefining the width of the fluid space parallel to each other in crosssection, and means for adjusting at least one end wall of the nozzle to vary the length of the fluid space in cross-section.

5. An ejector having a. nozzle serving as an operating or jet nozzle, and formed with a fluid space elongated in cross-section and its opposite walls defining the width of the fluid space parallel to each other in crosssection, and means for adjusting at least one end wall of the nozzle to vary the length of the fluid space in cross-section.

6. An ejector having a nozzle serving as a difiuser or combining tube, said nozzle being formed with a fluid space elongated in cross section and its opposite walls defining the width of the fluid space parallel to each other in cross-section, and means for adjusting at least one end wall of the nozzle to vary the length of the fluid space in crosssection.

7. An ejector having an operating fluid nozzle and a diffuser or combining tube, each formed with a fluid space elongated in cross-section and having its opposite walls defining the width of the fluid space parallel to each other in cross-section, and means for adjusting the end walls of the nozzle and tube to vary the length ot the fluid space in cross-section. I

8. In asteam air ejector, the combination with a steam nozzle having a jet space with one dimension in cross-section narrow relatively to the other, of an air-receiving chamber, and a diffuser or combining tube receiving the steam and air and having its combining space of two different dimensions in cross-section with the larger and smaller dimensions in the same planes as the larger and smaller dimensions of the steam nozzle.

9. In a steam air ejector, the con'ibination with a steam nozzle having a jet space with one dimension in cross-section narrow relatively to the other, o't an air-receii-"ing chamber, and a diffuser or combining tube receiving the steam and air and having its combining space oi" two dimensions in crosssection, and means for adjusting the nozzle.

to vary the larger dimension of the ct space.

10. In a steam air ejector, the combination with a steam nozzle having a jet space with one dimension in cross-section narrow relatively to the other, of an air-receiving chamber, and a diff ser or combining tube receiving the steam and air and having its combining space oi? two different dimensions in cross-section, and means for adjusting the nozzle and dilluser to'vary the larger dimension of the jet and combining spaces.

11. An ejector nozzle having two fixed side walls separated from each other to form aslot whose width of opening at any crosssection is small relatively to its length, said ejector also having at least one movable end wall to move into the slot to vary the length oi said slot, said parts being so proportioned that at the smallest section of the nozzle the length of the slot at its minimum length is at least 25 times the width of the slot.

12. An ejector nozzle having two fixed side walls separated from each other to form a slot whose width of opening at any cross-section is small relatively to its length, said parts being so proportioned that at the smallest section of the nozzle the length of the slot is at least 25 times the Width of the slot. V

In testimony whereof, I have hereunto set my hand.

- CHARLES E. LUOKE. 

